This invention relates to mechanisms for pulling a web of paper through a printing press. The web is passed through a series of printing components and driers. As each component makes its impression onto the web with wet inks, the web becomes damp. It is mandatory that the web be drawn taut at a constant rate to prevent the web from curling, warping or shrinking or otherwise deforming. Such deformations can be accentuated if the pullout rollers, also known as trolley assemblies, are not accurately positioned to the power rollers toward which the pullout rollers are continuously biased to grasp the paper therebetween. The power rollers are generally of considerable length and several pullout rollers are normally paired with each power roller.
It is not only important to maintain equal pressure between each pair of rollers on the web, but the pairs of rollers must be maintained in parallelism. Otherwise, the non-parallel roller combinations tend to skew the web and to deform the sections of the paper running between them. In sheeting operations random sheet lengths occur if the sheet is not drawn evenly or the sheet is allowed to shrink unevenly.